A user may be associated with one or more contact collections, each including one or more contact entries. For example, a user may have a contact collection on a mobile phone that includes contact entries each including one or more properties of an entity such as a name, phone number, and/or email address of the entity. Also, for example, the user may have a contact collection associated with an email service that includes contact entries each including one or more properties of an entity. A user may find it burdensome to maintain complete information and/or to update information in one or more of the contact collections.